: 303-14
Discovery 3/LR3 - Engine DTC P0171 and/or P0174
AFFECTED VEHICLE RANGE:
Discovery 3 / LR3
Model Year:
Up to 2007
VIN:
5A300394-6A413981
Engine:
4.4L AJV8
MARKETS:
All
CONDITION SUMMARY:
Situation: A customer may report a concern that the malfunction indicator lamp (MIL)/check engine lamp (CEL) is illuminated but has no drivability issues. Investigation using diagnostic equipment reveals diagnostic trouble codes (DTCs), P0171 and/or P0174 - Fuel mixture too lean.
Cause:
The engine management system has detected that extra fuel is required to keep the system in specification. In most cases, an air intake system leak after the mass air-flow (MAF) sensor will cause the above complaint and air intake system leaks should be diagnosed and rectified.
This bulletin is not a diagnostic aid for air leaks, however listed are the known most common causes of air leaks which cause the DTC to be set.
Most Common Causes:
• Engine oil dipstick not full seated and/or damaged 'O' ring.
• Engine oil filler cap not seated correctly.
• Engine oil filler tube not seated correctly and or seal damaged.
• Engine breather hoses not fully seated and clips not secured correctly.
• Engine positive crankcase ventilation (PCV) valve leaking at cam cover.
• Vacuum pipes not correctly latched/secured.
Less Common Causes:
• Intake manifold sealing.
• Exhaust gas recirculation (EGR) valve sleeve preventing the intake manifold seating correctly.
• Acoustic pack under intake manifold preventing the intake manifold seating correctly.
Where no intake air leaks are present, a software calibration sensitivity issue can also cause the above complaint.
Action: Should a customer express concern regarding the above and no intake air leaks are found, refer to the Service Procedure detailed in this bulletin to update the engine control module software.
TOOLS:
Integrated Diagnostic System (IDS) with DVD 103 or later and patch file 3 installed (available on GTR).
IDS
WARRANTY:
noteNOTE: Repair procedures are under constant review, and therefore times are subject to change; those quoted here must be taken as guidance only. Always refer to TOPIx to obtain the latest repair time.
noteNOTE: DDW requires the use of causal part numbers. Labor only claims must show the causal part number with a quantity of zero.
DESCRIPTION
SRO
TIME
CONDITION CODE
CAUSAL PART
Tune - download - engine control module
12.90.13
0.20 hours
07
NNN500411
noteNOTE: Normal Warranty procedures apply.
SERVICE PROCEDURE:
1. If IDS with DVD 103 is being used and has previously had patch file 3 installed, continue from step 4. For information on how to confirm that the patch file has been installed onto IDS, refer to the patch process help file detailed in step 2.
2. noteNOTE: The software patch installation help file provides instructions for the patch file installation process and could take up to six minutes to download dependent on connection speed.
Download the IDS software patch installation help file from GTR:
1. Logon to GTR.
2. Select 'Home' from the menu at the top of the main page.
3. From the menus on the left of the page, select 'Diagnostics' as the 'Information Type' and select the relevant model and model year.
4. From the 'All Information' results, select 'Patch Files'.
5. Click the file link 'Patch Process Help File'.
3. noteNOTE: This could take up to twenty minutes to download dependent on connection speed.
Using the above help file, follow the instructions to download and install the software patch file into IDS and ensure IDS successfully restarts.
4. cautionCAUTION: Ensure the Midtronics CX Pro 25 or PSP550 - Vehicle Battery Conditioner/Power Supply is connected to the vehicle battery during diagnosis/module configuration and that the battery is sufficiently charged.
cautionCAUTION: Ensure that the diagnostic lead is correctly secured and cannot be accidentally disconnected during software update.
Connect the diagnostic equipment to the vehicle and begin an IDS session by entering the correct VIN for the current vehicle.
5. Note the current software levels of the engine control module:
1. Follow the prompts to read the vehicle configuration.
2. When prompted "Do you wish to read diagnostic trouble codes?", select "NO" and then press 'tick' to continue.
3. When the "Content Model" is displayed, select the 'Vehicle Configuration' tab.
4. Select 'Module Information'
5. Select 'Network integrity test'
6. Note the software part numbers displayed on the screen.
6. noteNOTE: During module configuration, check the on-screen software part number information that IDS will display during this step and compare to the software part number noted in step 5 above. If the same tune level is displayed, the vehicle already has the desired software level and the tune download process can be aborted.
Configure the control module:
1. Return to the 'Vehicle Configuration' screen and select 'Module Configuration'
2. Follow the on-screen prompts.
3. Select 'Configure Existing Modules'.
• From the sub-menu, select 'Engine Control Module'
4. Check the tick-box to continue and follow the on-screen instructions.
7. Repeat step 5 to confirm the software level change.
8. Exit the IDS session and disconnect the diagnostic equipment from the vehicle.
Cannot hurt and you probably need it.